The purpose of the clinical breast cancer research core is to support the research of the five SPORE projects, and the high priority projects and other studies of SPORE investigators. This will be done in several ways. Breast cancer patients seen in Medical Oncology and the benign breast and high risk women seen in the Comprehensive Breast Center will be available for SPORT studies. The Breast Cancer Section of the Vincent T. Lombardi Cancer Research Center currently evaluates about 400 new breast cancer patients per year, many of whom are second opinions from outside institutions. there are 271 new breast cancers recorded on the Georgetown University Tumor Registry annually. The Comprehensive Breast Center currently sees 592 new patients a year with 1,760 follow-up visits. The SPORE projects will draw patients from these resources. Also, the Lombardi Center will place public advertisements about the projects throughout the Washington, D.C. area to accrue more patients. There will be a special emphasis on minority patients, who will be recruited through collaborations with D.C. General Hospital, the D.C. Cancer Consortium, and Greater Southeast Hospital. At the present time several protocols are already in place. The SPORE will allow the addition of other breast cancer and chemoprevention protocols. A large database will be maintained on all patients involved in SPORE projects. This database will include information on demographics, risk analysis, family history, and the clinical and pathologic characteristics of malignant tumors and benign breast biopsy specimens. The investigator of each project and the Director of the Clinical Core will examine the data together to assure appropriate collection and transfer of materials and data, assure quality control, and draw conclusions regarding the hypothesis tested. A serum and lymphocyte DNA bank will be created from both benign breast and breast cancer patients' samples as a resource for the SPORE projects available through the SPORE Database Network. Appropriate clinical data will be recorded with each sample. This will be used for correlation with genetic markers, drug resistance markers and growth factors evaluated in the SPORE projects. The data management office will facilitate data entry, retrieval, protocol design and submission to the Institutional Review Board.